Control systems
First Claim
1. In a control system including two control lanes for processing nominally-identical data digitally to derive nominally-equivalent control outputs, and means for comparing said outputs with one another to respond to the existence of a failure, the improvement wherein different digital representations of the same nominally identical data are used in the processing of the same data in the two lanes so that context dependent features (as defined) are detected.
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Accused Products
Abstract
A quadruplex, double-failure survival, fly-by-wire aircraft control system includes two monitor lanes whose outputs are consolidated with those of the four main control lanes to drive the aircraft control-surfaces by hydraulic rams via individual spool-valve actuators. Nominally-identical sets of pilot'"'"'s-demand, instrument, and position-feedback signals are derived independently for the four lanes respectively, and digital representations of all these are exchanged between the control lanes for the selection of their mean or median values by digital processors that also serve to compute the control outputs of the lanes from the selected values. The sets of signals supplied to one pair of the four lanes are reversed in sense compared with the sets supplied to the other pair so as to ensure that the same digitally-encoded data is represented differently in the different pairs and the possibility of a context-dependent failure occurring simultaneously in both pairs is thereby avoided. The outputs of the control lanes are amalgamated to provide intermediate-value inputs to the monitor lanes. An alternative monitored-duplex single-failure survival fly-by-wire system has two control lanes with reversal of sense of input and feedback signals as between one lane and the other. Difference of digital representation in a third, monitor lane is provided by halving the amplitude of the input and feedback signals supplied to this lane.
67 Citations
9 Claims
- 1. In a control system including two control lanes for processing nominally-identical data digitally to derive nominally-equivalent control outputs, and means for comparing said outputs with one another to respond to the existence of a failure, the improvement wherein different digital representations of the same nominally identical data are used in the processing of the same data in the two lanes so that context dependent features (as defined) are detected.
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6. A plural-lane control system comprising:
- a plurality of means for processing data digitally to provide individual control outputs;
data-input means to manifest data to said processing means, said data-input means comprising first supply-means for supplying digital representations of said manifested data to a first of said processing means, and second supply-means for supplying digital representations of said manifested data to a second of said processing means, the said digital representations supplied to said second processing means by said second supply-means being different from the said digital representations supplied by said first supply-means to said first processing means in respect of the same data, so as to avoid simultaneous context-dependent failure in said first and second processing means; and
actuator means responsive to the control outputs of said first and second processing means to exert control in accordance therewith. - View Dependent Claims (7, 8, 9)
- a plurality of means for processing data digitally to provide individual control outputs;
Specification